Problems & Solutions

Integrated Waste Management Facilities

Objective

The Integrated Waste Management Facilities (IWMF) aims to substantially reduce the bulk size of mixed MSW and to recover useful resources. It will minimize the landfilling of waste significantly, thereby extending the useable life of landfills and their extensions in Hong Kong.

The IWMF will be developed in phases. The IWMF Phase 1 will have a treatment capacity of 3,000 tonnes each day. It will adopt advanced incineration as the core treatment technology as well as a demonstration scale mechanical sorting and recycling facility for recovery of useful resources from the mixed MSW.

Advanced technologies are able to reduce pollutant emissions from incineration effectively. For example in Germany, the amount of waste incinerated in year 2000 doubled that in 1990, but due to the adoption of advanced control technologies, the dioxin emission was only one-thousandth of that in 1990. Overseas experience and studies have also demonstrated that advanced incineration plants that comply with stringent emission standards will not cause adverse health impacts.

The IWMF Phase 1 will adopt state-of-the-art technologies and pollution control measures. Its emissions will comply with the emission standards for waste incineration facilities in Hong Kong and the European Commission for the protection of public health and the environment. The emission standard for nitrogen oxides will be even more stringent than the corresponding European Commission standard.

Air quality monitoring stations will be set up at Shek Kwu Chau (SKC), Cheung Chau and South Lantau to provide objective data on local air quality to ensure that the operation of the IWMF Phase 1 will not affect the surrounding environment. An action level will be set at 95% of the emission limits to provide early alarm such that we will take appropriate actions according to a formulated plan which will include ceasing the MSW feeding and preparing for shut down of the incineration system.

IWMF Phase 1 Site Selection

A comprehensive site selection exercise that aimed to determine potential sites for developing the IWMF was completed in January 2008. Two potential sites were identified, namely the Tsang Tsui Ash Lagoons site in Tuen Mun and the Shek Kwu Chau site (to be reclaimed) to the south of Lantau Island. The IWMF Phase 1 will occupy an area of about 10 hectares.

Potential Sites for the Development of IWMF

Tsang Tsui Ash Lagoons site

Shek Kwu Chau site

Engineering Investigation and Environmental Impact Assessment Studies

In November 2008, the government commenced a detailed Engineering Investigation and Environmental Impact Assessment Studies (EI&EIA Studies) for these two sites to ascertain their overall suitability. The EI&EIA Studies were completed in 2012. The EIA for IWMF Phase 1 was approved under the Environmental Impact Assessment Ordinance on 17th January 2012. The full approved EIA report is available at internet website (www.eia.hk).

Taking into account the EIA report results and Hong Kong’s overall waste management strategy as a whole, the Government has identified the artificial island near SKC as the preferred site for developing the first modern IWMF. Please refer to the Legislative Council Brief and the Environmental Affairs Panel Papers no.: 1. CB(1) 1369/11-12(01) and 2. CB(1) 1628/11-12(01) for more information.

Technology Review

Having reviewed different thermal treatment technologies, the EI&EIA Studies proposed that the moving grate incineration be adopted as the core technology for MSW treatment. The advantages of this technology are that :-

it has the best proven track record of application in large MSW treatment facilities (i.e. over 3,000 tonnes per day (tpd));

it is the most robust thermal technology, capable of treating different sizes and qualities of mixed MSW;

it possesses the least operational complexity; and

it requires the least capital and operating costs.

In December 2009, the Advisory Committee on the Environment (ACE) was consulted on the recommended moving grate incineration technology (ACE Paper, Annex A, Annex B and Minutes of Meeting, 14th Dec 2009 [ACE 22/2009] ). The ACE supported the recommended incineration technology and agreed that a mechanical sorting and recycling facility with a treatment capacity of 200 tonnes per day should be incorporated in the IWMF to test the operational viability and cost effectiveness of recovering the recyclables from the MSW prior to the incineration process.

Waste Transportation

For the artificial island near SKC, MSW compacted in tightly sealed containers and delivered by dedicated container vessels would be delivered by marine vessels from the existing refuse transfer stations including Island East Transfer Station, Island West Transfer Station and West Kowloon Transfer Station. For the Tsang Tsui Ash Lagoons site, MSW currently delivered to the berth of WENT Landfill by marine vessels or delivered directly to the WENT Landfill by land transport will be diverted from the WENT Landfill to the adjoining the Tsang Tsui Ash Lagoons site by land transport.

Waste Transportation Arrangement :

IWMF in Tsang Tsui Ash Lagoons site

Waste container vessel

IWMF in Shek Kwu Chau site

IWMF Phase 1 Contract

The Design-Build-Operate (DBO) contract for the IWMF Phase 1 was awarded in November 2017. The IWMF Phase 1 is expected to be fully commissioned by 2024 and the contract includes a 15-year operation period.

design and installation of the electrical and mechanical works for the waste receiving and sorting facilities, waste incineration, heat recovery, power generation, pollution control and ash treatment systems;

design and construction of mechanical and electrical works for utility services facilities including a desalination plant and a wastewater treatment plant.;

design and construction of power connection and export system; and

provision of pollution control and environmental monitoring facilities.

Environmental Education Facilities

The IWMF Phase 1 will have environmental education facilities that provide information on and demonstration of waste management in Hong Kong for the public. Drawing on experience from the T·PARK, guided tours will be provided to visitors for understanding the most advanced waste-to-energy technologies and appreciating the environmental features of the IWMF Phase 1.

An educational route will be designed for visitors to overlook the main components of IWMF Phase 1 and have a close-up learning experience at key areas such as the incineration process, flue gas treatment process, mechanical sorting and recycling facility and control room. Ferry services between the IWMF Phase 1 and Central/Cheung Chau will be offered to visitors.

Environmental Protection and Ecological Enhancement

Waste-to-Energy

The IWMF Phase 1 will recover heat energy from the MSW incineration process to produce about 480 million kilowatt-hours (kWh) of surplus electricity (amounts to about 1% of the total electricity consumption in Hong Kong) for export to the existing power grid in Hong Kong every year. The surplus electricity, which is equivalent to the output of 400 largest solar farms in Hong Kong at Siu Ho Wan Sewage Treatment Works, will be sufficient for use by 100,000 households.

Through the replacement of fossil fuel in electricity generation and reduction in the volume of MSW for landfill disposal, it is estimated that about 440,000 tonnes of greenhouse gas emission per year can be curtailed.

Surplus Electricity Export

Baseline Monitoring Surveys

Before the construction works of the IWMF Phase 1 starts near SKC, baseline monitoring surveys for Finless Porpoise, White-bellied Sea Eagle and hard coral have been conducted to determine their baseline conditions to ascertain the utilisation of the area by Finless Porpoise, the presence and breeding status of White-bellied Sea Eagle in the Shek Kwu Chau area and the number and location of hard coral colonies within the potentially affected areas according to the approved Environmental Monitoring & Audit Manual. These baseline monitoring surveys will be used to formulate the coral translocation plan and the detailed monitoring programme and mitigation measures to avoid disturbance to Finless Porpoise and White-bellied Sea Eagle during construction and operation.

Coral Survey

Finless Porpoise Monitoring

White-bellied Sea Eagle Monitoring

Non-dredged Reclamation

The artificial island near SKC will mainly be constructed by non-dredged method to minimize water quality impact. The marine deposits underlying the reclamation, including the seawalls and breakwaters, will be left in place to avoid dumping of dredged marine deposits.

An advanced ground treatment method, i.e. deep cement mixing (DCM) is proposed to reinforce the marine mud in situ to control settlements and movements of the reclamation to within acceptable limits and to ensure that the construction of the artificial island can be completed within a reasonable time frame.

The DCM will also be designed to ensure that the reclamation will be safe and any residual settlements and movements will not affect the operation and service of the IWMF Phase 1. Precast concrete structure will be used for the seawall and breakwater construction to minimize underwater acoustic disturbance to Finless Porpoise and water quality impacts during construction.

Deep Cement Mixing

Eco-shoreline

The blockwork seawall facing Shek Kwu Chau will be designed as environmentally friendly eco-shorelines with features to provide more suitable habitats for colonisation of intertidal and subtidal species and thereby enhance the ecological functions of the coastal habitats. Example of environmentally friendly seawalls with enhanced ecological features to simulate the natural habitat variability of SKC and to encourage wildlife uses by increasing the shoreline complexity is shown below:

The IWMF Phase 1 will be designed with a net zero discharge of wastewater by equipping with a wastewater treatment plant on-site to provide treatment to wastewater generated from the facilities for reuse in the incineration plant and the mechanical sorting and recycling facility or for washdown and landscape irrigation in the IWMF Phase 1.

Water Balance Schematic Diagram

Marine Park

Finless Porpoise, a species of conservation interest, is protected under the Wild Animals Protection Ordinance (Cap. 170) and the Protection of Endangered Species of Animals and Plants Ordinance (Cap. 586) in Hong Kong. The waters of South Lantau including the area near Shek Kwu Chau are an important habitat for Finless Porpoise. To compensate for the permanent loss of 31 hectares habitat for Finless Porpoise as a result of the reclamation works and breakwater construction for the IWMF Phase 1, a compensatory marine park with an area of 797 hectares is proposed to be established in the waters between Soko Islands and Shek Kwu Chau.

Habitat Ratings of Finless Porpoises between 2005 and 2014

In the immediate vicinity of the proposed compensatory marine park, there is a proposed Soko Islands Marine Park initiated by the Agriculture, Fisheries and Conservation Department with an area of approximately 1,270 hectares for conserving important habitats of Chinese White Dolphin and Finless Porpoise, where the waters of Soko Islands are considered a unique location with both Chinese White Dolphin and Finless Porpoise regularly sighted.

The proposed South Lantau Marine Park

To achieve better synergy in the future management and operation of the marine parks, and taking into account the sizable movement ranges and high mobility of Chinese White Dolphin and Finless Porpoise, it is proposed to combine the proposed compensatory marine park and the proposed Soko Islands Marine Park into a larger single marine park of approximately 2,067 hectares, namely the South Lantau Marine Park. The statutory process of the South Lantau Marine Park designation is targeted to be completed by 2019. Upon designation, it will be the largest marine park in Hong Kong.

Fisheries Enhancement Measures

Deployment of artificial reefs and release of fish fry and fingerlings have been proposed with a view to enhancing the fisheries resources in South Lantau waters. The artificial reefs are recommended to be deployed at the core area of the proposed South Lantau Marine Park where all fishing activities are prohibited, so that the aggregated fisheries resources can be adequately protected.

Suggested designs of prefabricated concrete artificial reef units

In addition, fish fry and fingerlings will be released at the deployed artificial reefs within the proposed South Lantau Marine Park and at the eco-shoreline to be constructed under the IWMF Phase 1 to further enhance the fisheries resources in South Lantau waters.

To evaluate the effectiveness of the artificial reefs deployment and fish restocking as fisheries enhancement measures, a series of monitoring works including fisheries resources monitoring by gill netting and hand lining, artificial reef structural monitoring by side-scan sonar and fish restocking monitoring by hand lining will be conducted.

The proposed location for artificial reefs development

Restocking of fish fry / fingerlings at artificial reefs

Material Recovery

Mechanical Sorting and Recycling Facility

The mechanical sorting and recycling facility will make use of automatic waste sorting technology to recover useful resources, such as ferrous metal, non-ferrous metal, plastics and glass, from up to 200 tonnes of MSW per day.

Mechanical Sorting and Recycling Facility

Bottom Ash

During the incineration process, the non-combustible residue of combustion in the incineration system, i.e. bottom ash, will be collected and magnetic separators will extract ferrous metals from the bottom ash for recovery. Opportunities for recycling or other beneficial use of the bottom ash will be further explored during the design and construction period.

Bottom Ash Treatment

Architectural and Landscaping Design

The architectural and landscaping design of the IWMF Phase 1 will embrace the environmental philosophy of "Green, Clean and Lean" so as to blend in with the surrounding environment. We will also strive to acquire the green building rating accreditation of BEAM Plus Gold or a higher rating for the project.

Community Liaison

As set out in the Policy Address 2014, the Government has pledged to ensure that waste treatment facilities shall meet high environmental and operational standards, and will continue to strengthen communication with local communities regarding the facilities including their management, delivery arrangements, environmental monitoring and hygiene to minimize potential impacts on residents.

2014 Policy Address

To this end, an Islands District Liaison Group comprising representatives from the Islands District Council, relevant Rural Committees, stakeholders including the fishery sector and relevant government departments, was established in July 2015 with a view to strengthening communication with the local communities for the implementation of major waste treatment facilities (including IWMF Phase 1, Organic Resources Recovery Centre Phase 1 and refuse transfer stations) in the Islands District.

In accordance with our previous IWMF Phase 1 related engagement experience, different local communities will have different interests and concerns. In this connection, 3 working groups namely the South Lantau Working Group, Cheung Chau Working Group, and Shek Kwu Chau Working Group were formed in July 2015 under the umbrella of Islands District Liaison Group to strengthen our communications with the local communities with a view to catering for their different needs and interests.

Islands District Liaison Group

We will continue with the public engagement process and convene meetings under the Island District Liaison Group on a regular basis.